Rhinoceros horns have long been a target for poachers. And recently, demand has increased and pushed up the prices on the black market.

ADAM HIGGINBOTHAM: Rhino horns have gone from being what was - has been a staple of Chinese traditional medicine for hundreds of years to being something that is a talisman of conspicuous consumption by high rollers and members of the new wealthy elite.

RATH: That's Adam Higginbotham. He's a contributor to Bloomberg Businessweek, and he says that the horns, by weight, are now more valuable than cocaine or heroine. And one group of poachers, far away from the rhinos' native habitat, have tried to profit.

HIGGINBOTHAM: They decided that it was much easier to go after rhinos that were long dead and therefore easier to get hold of and less angry about the prospect of being hunted.

RATH: We're talking about stuffed rhinos, museum pieces. Here's how this played out. A few years back, museums across Europe began to get suspicious visits.

HIGGINBOTHAM: So they would go into the museums during the day and have a look round, ask to see any rhino exhibits that the museum curators recommended or anything unusual that they had in the museums. And they wander around, find out where they were, takes some pictures of them with their phones. And then they'd leave.

And then frequently what would happen is a few days or a few hours later, somebody else would come in. And on one occasion, a couple of men distracted the museum guards or the curators by having a chat with them about something they thought was interesting while their accomplices ran upstairs. One got onto the shoulders of another, and using a hammer, smashed the horn off the nose of a stuffed rhino trophy that was mounted on the wall. And then they just ran out again with it.

RATH: Not exactly cat burglar, jewel thief types.

HIGGINBOTHAM: No. There's no kind of Cary Grant or "Ocean's Eleven"-style sophistication to any of these robberies.

RATH: Since 2011, 15 European countries reported 67 similar robberies. Authorities and museum curators were at a loss. Until investigators discovered the thieves all came from one area.

HIGGINBOTHAM: It turned out after several years of investigation that this series of apparently baffling robberies was being organized by a single network who were part of the Irish traveling community, and they originate in this small town two hours drive out of Dublin.

RATH: Higginbotham describes Irish Travellers as a group of merchants who spend much of the year trading antiques around Europe and the rest of the world.

EAMON DILLON: They're just experts at it. They do it every day nonstop, and they've been doing it since the age of 10 or 11 or 12. So I mean, you know, they're up there with any Harvard graduate when it comes to like figuring out how to close a deal.

RATH: That's Eamon Dillon. He's an editor and crime reporter for the Sunday World in Dublin. He says suspicion fell on one group of traders known as the Rathkeale Rovers, named for their small town in central Ireland. Dillon says the group brought their knowledge of rare commodities and Europe's complicated jurisdictions to the world of rhino horn smuggling.

DILLON: And obviously, Europe, you know, there wouldn't necessarily be a lot of cooperation between different police forces, so, you know, it's quite easy for someone to organize a theft in the Czech Republic while, you know, waiting in a van 50 miles away in Germany or Austria or wherever.

RATH: In 2010, Europol organized a joint task force of 33 European nations to bring down the Rovers. Last September, they staged several raids and arrested a handful of the gang's leaders. The punishments varied. Some men were fined, others had their charges dropped, and a few still await sentencing. Perhaps as a consequence, rhino horn thefts have declined over the past few months. But Adam Higginbotham has another explanation for why that may be.

HIGGINBOTHAM: Aside from the arrests and the Europol operation, one Irish policeman told me that the reason that the number of robberies has declined is simply because the Rathkeale Rovers had stolen them all.

RATH: That's Adam Higginbotham. He's a contributor to Bloomberg Businessweek. His article in the January issue is called "The Rhino Racket." Transcript provided by NPR, Copyright NPR.